Metal expansion nuts, often referred to as expansion anchors or expansion inserts, are specialized fasteners that expand when a bolt or screw is threaded into them. They typically consist of a cylindrical body with slits along its length or an expandable design that facilitates outward expansion. The main purpose of these nuts is to create a secure grip within a substrate, such as concrete, wood, or metal, thereby preventing loosening due to vibrational forces, temperature fluctuations, or stress.

5. Versatility Beyond chipboard, these screws can also be utilized in various materials, including plywood, MDF, and even softer woods, making them an essential tool in any carpenter’s or DIY enthusiast's toolkit.

2. Masonry Anchors Specifically designed for use in concrete or brick, masonry anchors offer significant holding power. They require a pre-drilled hole, and as the anchor is inserted, it expands, creating a tight fit within the masonry.